Pretty Nice!
Very nice! I like it. Musically the tune certainly sounds like it fits the Nintendo music theme. In that regard it more then accomplishes what it set out to do!
I'm not entirely sure what 8-bit music means. I have a pretty good idea that it means Nintendo music and they call it 8-bit for copyright issues? Ha, I honestly don't know, so I could be way off with this next part.
For this to be purist NES music I think your channels are off. The NES had only 3 melodic channels! Two pulse wave channels which had changeable but preset duty cycles, and one triangle channel with limited range. Then it also had a noise channel for drums and a DPCM sampler channel.
I hear too many oscillators in your tune for me to pick them all out! Remember the NES had 3 melodic oscillators total, only one oscillator per channel, and could play a max of 3 notes at a time, one on each channel, that's all!
Also the guys who made that music wrote it out in a programming language, kind of gives you a certain respect for those guys who made nintendo music back in the day, huh?